March 2019

Astronauts leave behind many things when they boldly go. Bacteria, however, stay with them. Extreme spaceflight conditions can force these bacteria to toughen up, while simultaneously lowering the immune defenses of the stressed, isolated crew. These effects - and the risk of infection - grow with mission duration.

Nitric oxide is a fascinating and versatile molecule, important for all living things as well as our environment: It is highly reactive and toxic, it is used as a signaling molecule, it depletes the ozone layer in our planet's atmosphere and it is the precursor of the greenhouse gas nitrous oxide (N2O).

This paper outlines some of the possible advancements for the technosignatures searches using the new methods currently rapidly developing in computer science, such as machine learning and deep learning.

Astrobiology is the study of the origin, evolution, distribution, and future of life in the universe. It is an inherently interdisciplinary field that encompasses astronomy, biology, geology, heliophysics, and planetary science, including complementary laboratory activities and field studies conducted in a wide range of terrestrial environments. Combining inherent scientific interest and public appeal, the search for life in the solar system and beyond provides a scientific rationale for many current and future activities carried out by the National Aeronautics and Science Administration (NASA) and other national and international agencies and organizations.

Some atmospheric gases have been proposed as counter indicators to the presence of life on an exoplanet if remotely detectable at sufficient abundance (i.e., antibiosignatures), informing the search for biosignatures and potentially fingerprinting uninhabited habitats.

The solar tide in an ancient Venusian ocean is simulated using a dedicated numerical tidal model. Simulations with varying ocean depth and rotational periods ranging from -243 to 64 sidereal Earth days are used to calculate the tidal dissipation rates and associated tidal torque.

The habitability of a planet depends on various factors, such as delivery of water during the formation, the co-evolution of the interior and the atmosphere, as well as the stellar irradiation which changes in time.

A study by scientists at The Australian National University (ANU) on the magnetic fields of planets has found that most planets discovered in other solar systems are unlikely to be as hospitable to life as Earth.

The TRAPPIST-1 system is sufficiently closely packed that tides raised by one planet on another are significant. We investigate whether this source of tidal heating is comparable to eccentricity tides raised by the star.

There is now solid experimental evidence of at least one supernova explosion within 100 pc of Earth within the last few million years, from measurements of the short-lived isotope 60Fe in widespread deep-ocean samples, as well as in the lunar regolith and cosmic rays.

The study of the composition of brown dwarf atmospheres helped to understand their formation and evolution. Similarly, the study of exoplanet atmospheres is expected to constrain their formation and evolutionary states.

Scientists looking for signs of life beyond our solar system face major challenges, one of which is that there are hundreds of billions of stars in our galaxy alone to consider. To narrow the search, they must figure out: What kinds of stars are most likely to host habitable planets?

Tidal heating is the prime suspect behind Enceladus's south polar heating anomaly and global subsurface ocean. No model of internal tidal dissipation, however, can explain at the same time the total heat budget and the focusing of the energy at the south pole.

Last August, Abdelrhman Mohamed found himself hiking deep into the wilderness of Yellowstone National Park. Unlike thousands of tourists who trek to admire the park's iconic geysers and hot springs every year, the WSU graduate student was traveling with a team of scientists to hunt for life within them.

An international team of researchers, which includes scientists from McMaster's School of Geography & Earth Sciences, NASA, and others, is tackling one of the biggest problems of space travel to Mars: what happens when we get there?

WHY WE PERFORMED THIS AUDIT: Supporting scientific and technological research to reveal the unknown about Earth, its Sun and solar system, and the universe for the benefit of humankind is an important part of NASA's mission. In 2017, NASA spent approximately $600 million on this type of research largely through grants and cooperative agreements.

Multiple lines of evidence point to one or more moderately nearby supernovae, with the strongest signal ~2.6 Ma. We build on previous work to argue for the likelihood of cosmic ray ionization of the atmosphere and electron cascades leading to more frequent lightning, and therefore an increase in nitrate deposition and in wildfires.

Typically, H3+ is formed by collisions involving hydrogen gas, but its chemistry at the molecular level is relatively unknown. When organic molecules are hit by a laser pulse, they are ionized and the reaction begins.

NASA has decided to replace the current magnetometer on the upcoming Europa Clipper mission with a less complex instrument. The Europa Clipper mission, launching in the 2020s, will be the first dedicated and detailed study of a probable ocean world beyond Earth.

For almost a decade, astronomers have tried to explain why so many pairs of planets outside our solar system have an odd configuration -- their orbits seem to have been pushed apart by a powerful unknown mechanism.

A team led by Ludwig-Maximilians-Universitaet (LMU) in Munich paleontologist Adriana López-Arbarello has identified three hitherto unknown fossil fish species in the Swiss Alps, which provide new insights into the diversification of the genus Eosemionotus.